[boot] Improve bootloader allocation accounting

The bootloader relied on the kernel to know which parts of memory to not
allocate over. For the future shift of having the init process load
other processes instead of the kernel, the bootloader needs a mechanism
to just hand the kernel a list of allocations. This is now done through
the new bootloader allocator, which all allocation goes through. Pool
memory will not be tracked, and so can be overwritten - this means the
args structure and its other structures like programs need to be handled
right away, or copied by the kernel.

- Add bootloader allocator
- Implement a new linked-list based set of pages that act as allocation
  registers
- Allow for operator new in the bootloader, which goes through the
  global allocator for pool memory
- Split memory map and frame accouting code in the bootloader into
  separate memory_map.* files
- Remove many includes that could be replaced by forward declaration in
  the bootloader
- Add a new global template type, `counted`, which replaces the
  bootloader's `buffer` type, and updated kernel args structure to use it.
- Move bootloader's pointer_manipulation.h to the global include dir
- Make offset_iterator try to return references instead of pointers to
  make it more consistent with static array iteration
- Implement a stub atexit() in the bootloader to satisfy clang

src/boot/main.cpp

@@ -7,6 +7,7 @@
 #include <stddef.h>
 #include <stdint.h>
 
+#include "allocator.h"
 #include "console.h"
 #include "cpu/cpu_id.h"
 #include "error.h"
@@ -14,6 +15,7 @@
 #include "hardware.h"
 #include "loader.h"
 #include "memory.h"
+#include "memory_map.h"
 #include "paging.h"
 #include "status.h"
 
@@ -50,49 +52,14 @@ void change_pointer(T *&pointer)
 	pointer = offset_ptr<T>(pointer, kernel::memory::page_offset);
 }
 
-/// Allocate space for kernel args. Allocates enough space from pool
-/// memory for the args header and the module and program headers.
-init::args *
-allocate_args_structure(
-	uefi::boot_services *bs,
-	size_t max_modules,
-	size_t max_programs)
-{
-	status_line status {L"Setting up kernel args memory"};
-
-	init::args *args = nullptr;
-
-	size_t args_size =
-		sizeof(init::args) + // The header itself
-		max_modules * sizeof(init::module) +  // The module structures
-		max_programs * sizeof(init::program); // The program structures
-
-	try_or_raise(
-		bs->allocate_pool(uefi::memory_type::loader_data, args_size,
-			reinterpret_cast<void**>(&args)),
-		L"Could not allocate argument memory");
-
-	bs->set_mem(args, args_size, 0);
-
-	args->modules =
-		reinterpret_cast<init::module*>(args + 1);
-	args->num_modules = 0;
-
-	args->programs =
-		reinterpret_cast<init::program*>(args->modules + max_modules);
-	args->num_programs = 0;
-
-	return args;
-}
-
 /// Add a module to the kernel args list
 inline void
 add_module(init::args *args, init::mod_type type, buffer &data)
 {
-	init::module &m = args->modules[args->num_modules++];
+	init::module &m = args->modules[args->modules.count++];
 	m.type = type;
-	m.location = data.data;
-	m.size = data.size;
+	m.location = data.pointer;
+	m.size = data.count;
 
 	change_pointer(m.location);
 }
@@ -121,7 +88,7 @@ check_cpu_supported()
 
 /// The main procedure for the portion of the loader that runs while
 /// UEFI is still in control of the machine. (ie, while the loader still
-/// has access to boot services.
+/// has access to boot services.)
 init::args *
 uefi_preboot(uefi::handle image, uefi::system_table *st)
 {
@@ -129,33 +96,36 @@ uefi_preboot(uefi::handle image, uefi::system_table *st)
 
 	uefi::boot_services *bs = st->boot_services;
 	uefi::runtime_services *rs = st->runtime_services;
+
+	memory::init_allocator(bs);
 	memory::init_pointer_fixup(bs, rs);
 
-	init::args *args =
-		allocate_args_structure(bs, max_modules, max_programs);
+	init::args *args = new init::args;
+	g_alloc.zero(args, sizeof(init::args));
+	args->programs.pointer = new init::program[5];
+	args->modules.pointer = new init::module[5];
 
 	args->magic = init::args_magic;
 	args->version = init::args_version;
 	args->runtime_services = rs;
 	args->acpi_table = hw::find_acpi_table(st);
-	paging::allocate_tables(args, bs);
-
 	memory::mark_pointer_fixup(&args->runtime_services);
 
+	paging::allocate_tables(args);
+
 	fs::file disk = fs::get_boot_volume(image, bs);
 
-	buffer symbols = loader::load_file(disk, L"symbol table", L"symbol_table.dat",
-				uefi::memory_type::loader_data);
+	buffer symbols = loader::load_file(disk, L"symbol table", L"symbol_table.dat");
 	add_module(args, init::mod_type::symbol_table, symbols);
 
 	for (auto &desc : program_list) {
 		buffer buf = loader::load_file(disk, desc.name, desc.path);
-		init::program &program = args->programs[args->num_programs++];
-		loader::load_program(program, desc.name, buf, bs);
+		init::program &program = args->programs[args->programs.count++];
+		loader::load_program(program, desc.name, buf);
 	}
 
     // First program *must* be the kernel
-    loader::verify_kernel_header(args->programs[0], bs);
+    loader::verify_kernel_header(args->programs[0]);
 
 	return args;
 }
@@ -165,9 +135,14 @@ uefi_exit(init::args *args, uefi::handle image, uefi::boot_services *bs)
 {
 	status_line status {L"Exiting UEFI", nullptr, false};
 
-	memory::efi_mem_map map =
-		memory::build_kernel_mem_map(args, bs);
+	memory::efi_mem_map map;
+	map.update(*bs);
 
+	args->mem_map = memory::build_kernel_map(map);
+	args->frame_blocks = memory::build_frame_blocks(args->mem_map);
+	args->allocations = g_alloc.get_register();
+
+	map.update(*bs);
 	try_or_raise(
 		bs->exit_boot_services(image, map.key),
 		L"Failed to exit boot services");
@@ -194,8 +169,7 @@ efi_main(uefi::handle image, uefi::system_table *st)
 	// Map the kernel to the appropriate address
 	init::program &kernel = args->programs[0];
 	for (auto &section : kernel.sections)
-		if (section.size)
-			paging::map_section(args, section);
+		paging::map_section(args, section);
 
 	memory::fix_frame_blocks(args);
 
@@ -209,8 +183,10 @@ efi_main(uefi::handle image, uefi::system_table *st)
 
 	change_pointer(args);
 	change_pointer(args->pml4);
-	change_pointer(args->modules);
-	change_pointer(args->programs);
+	change_pointer(args->modules.pointer);
+	change_pointer(args->programs.pointer);
+	for (auto &program : args->programs)
+		change_pointer(program.sections.pointer);
 
 	status.next();